1. Technical Field
The present invention relates to a switch apparatus and a test apparatus.
2. Related Art
A semiconductor switch such as a field-effect transistor (FET) may be used as a switch apparatus that is configured to switch whether an electrical signal is allowed to be transmitted or blocked from being transmitted as disclosed in, for example, Japanese Patent Application Publication No. 06-244694.
However, such a semiconductor switch can only be used when the electrical signal has a narrow range of voltages. In particular, while the semiconductor switch allows the electrical signal to be transmitted, increasing the voltage of the input signal in the positive direction causes an increase in the difference between the gate voltage and the voltage of the input signal, which may cause the semiconductor switch to start blocking the electrical signal from being transmitted. Likewise, while the semiconductor switch blocks the electrical signal from being transmitted, increasing the voltage of the input signal in the negative direction causes a decrease in the difference between the gate voltage and the voltage of the input signal, which may cause the semiconductor switch to start allowing the electrical signal to be transmitted. If an offset voltage is applied to the gate electrode according to the voltage of the electrical signal for the purpose of widening the range of the voltages of the electrical signal, the gate-source voltage may vary depending on the direction of the current flowing through the semiconductor switch. As discussed above, there were difficulties in enlarging the range of voltages of the electrical signal that is controlled to be transmitted or not by the semiconductor switch while achieving symmetrical characteristics for the on resistance irrespective of the direction of the current.